泥质粉砂岩山岭公路隧道围岩变形

Surrounding rock deformation of argillaceous siltstone tunnel in mountain road

为分析不同围岩级别对泥质粉砂岩隧道的影响，依托贵州沙家坪隧道不同围岩级别的拱顶沉降和周边收敛进行分析；同时考虑隧道浅埋段多为破碎岩体，是隧道开挖工程中最危险地段；结合沙家坪隧道进出口地表浅埋段埋深数据，分析浅埋段埋深深度对拱顶沉降的影响。研究结果表明：泥质粉砂岩隧道相对其他岩类（峨眉山玄武岩、灰岩）隧道在低围压下流变滞后现象较明显，不易发生瞬态破坏，洞口段与中间深埋段围岩变形相差不大；拱顶沉降主要集中在距离洞口100～200m地下水和煤层较发育地段，平均沉降为-7mm，累计沉降在-8mm上下波动，同时煤层对隧道围岩的变形存在重大安全隐患；距离洞口0～60m隧道的累积周边收敛值及波动较大；对于泥质粉砂岩隧道，浅埋段埋深厚度对隧道围岩变形影响较弱。

In order to analyze the impact of different levels of surrounding rock on argillaceous siltstone tunnel, the information of vault subsidence and surrounding rock convergence of Shajia- ping tunnel in Guizhou province was used for analysis. The shallow-buried segment of tunnel was the most dangerous area with fractured rock. The data of shallow-buried segment of entrances and exits were used to analyze the influence of shallow-buried depth on vault subsidence. The re- sults show that relative to other rock （Emeishan basalt, limestone） tunnels argillaceous siltstone tunnel in low confining pressures is easy to have rheological lagging but not easy to have transient damage, and surrounding rock deformations in the tunnel mouth segment and intermediate buried section have on difference. Vault subsidence mainly concentrates in the groundwater and coal seam development area 100 to 200 m around the mouth of the tunnel, the average settlement is --7 mm and cumulative settlement is fluctuating around --8 mm. At the same time the coal seam is a hidden trouble for the deformation of surrounding rock. About 0-60 m from the mouth the accumulation of peripheral convergence value changes obviously for the argillaceous siltstone tun- nel, the depth of shallow-buried segment has little influence on the deformation of the surround- ing rock. 2 tabs, 9 figs, 11 refs.